Nearly all pediatricians and family physicians have encountered parents who want to delay their infants’ vaccinations, a study published March 2 in Pediatrics suggests.

A national survey of 534 doctors showed that in a typical month, 93 percent of doctors have interacted with parents who want to delay a shot for a child age 2 or younger. Most doctors who encountered a vaccine delay request complied, saying that agreement would build trust with the families. About one-fifth of survey respondents reported that 10 percent or more of parents asked to delay or space out shots beyond the vaccine schedules developed by experts.

The new survey was completed before the current outbreak of measles that arose from unvaccinated people visiting Disneyland in southern California in December. As of February 27, the CDC reports that that outbreak has spawned 170 cases of measles in 17 states and the District of Columbia since January 1.